1. Field of the Invention
This invention relates to a spindle motor used in a disk drive. More particularly, this invention relates to a spindle motor having a stator support structure supporting one of the inner and outer diameters of a stator.
2. Description of the Prior Art and Related Information
A huge market exists for disk drives such as hard disk drives for mass-market host computer systems such as servers, desktop computers, laptop computers, and consumer electronics devices such as a digital video recorder (“DVR”). To be competitive in this market, a hard disk drive must be relatively inexpensive, and must accordingly embody a design that is adapted for low-cost mass production. In addition, it must provide substantial capacity, rapid access to data, reliable performance, and in certain acoustic-sensitive applications such as consumer electronics devices, low acoustics. Numerous manufacturers compete in this huge market and collectively conduct substantial research and development, at great annual cost, to design and develop innovative hard disk drives to meet increasingly demanding customer requirements.
Each of numerous contemporary mass-market hard disk drive models provides relatively large capacity, often in excess of 80 gigabytes per drive. Nevertheless, there exists substantial competitive pressure to develop mass-market hard disk drives that have even higher capacities and that provide rapid access. Another requirement to be competitive in this market is that the hard disk drive must conform to a selected standard exterior size and shape often referred to as a “form factor.” Generally, capacity is desirably increased without increasing the form factor or the form factor is reduced without decreasing capacity.
Satisfying these competing constraints of low-cost, small size, high capacity, low acoustics, and rapid access requires innovation in each of numerous components and methods of assembly including methods of assembly of various components into certain subassemblies. Typically, the main assemblies of a hard disk drive are a head disk assembly and a printed circuit board assembly.
The head disk assembly includes an enclosure including a base and a cover, at least one disk having at least one recording surface, a spindle motor for causing each disk to rotate, and an actuator arrangement. The printed circuit board assembly includes circuitry for processing signals and controlling operations. Actuator arrangements can be characterized as either linear or rotary; substantially every contemporary cost-competitive small form factor drive employs a rotary actuator arrangement.
The spindle motor includes a stator, which typically includes a plurality of laminated stator teeth with a coil wound around the teeth. The stator may be attached to a surface of a spindle motor bracket such that the stator teeth and the coil are cantilevered; for example, an inner diameter of the stator may be attached to the surface of the spindle motor bracket. When the spindle motor is spun up in a disk drive, the stator may vibrate at its natural frequencies, generally between 10 KHz and 20 KHz. Such vibrations from the stator may lead to higher acoustics, which may exceed the acoustic requirements in certain acoustic-sensitive applications such as consumer electronics devices.